The Nagasaki District Court ordered local authorities to certify the 15 individuals as atomic bomb survivors, despite their location being beyond the officially recognized zone but within a 12-kilometer radius of the bomb's hypocenter.
Presiding Judge Shinsuke Matsunaga said, "There is a relevant probability that nuclear fallout was observed in the east Nagasaki district where the 15 were when the bomb exploded," basing the decision on government surveys.
The ruling could affect about 6,300 individuals who experienced the bombing within the expanded radius, according to the Nagasaki prefectural government.
This decision follows Prime Minister Fumio Kishida's recent instruction to the welfare minister to develop a relief package for such individuals, after meeting with their representatives on Aug. 9, the 79th anniversary of the Nagasaki bombing.
The case highlights ongoing efforts to address discrepancies in the treatment of atomic bomb survivors in Nagasaki and Hiroshima, where a 2021 high court ruling extended benefits to 84 people exposed to radioactive "black rain" outside the previously recognized area.
The plaintiffs in the Nagasaki case claimed they developed illnesses after exposure to radioactive particles or consuming contaminated food and drink, while local governments argued that their radiation exposure was insufficient to cause health damage.